银纳米粒子有序自组装体中偶联分子的表面增强拉曼光谱研究

Surface-enhanced Raman Spectroscopy of the Coupling Molecules in Self-assemblies of Silver Nanoparticles

采用自组装方法 ,分别以 1 ,4-二巯基苯和对巯基苯胺为偶联分子 ,在光滑银基底表面上构筑了银纳米粒子的单层和双层有序结构 .表面增强拉曼光谱研究表明 ,在有序银纳米粒子组装体中偶联分子的拉曼散射得到很大增强 ,其中 1 ,4-对巯基苯的拉曼散射增强效应主要来自光滑银基底表面与单层银纳米粒子间的电磁耦合 ,而对巯基苯胺的拉曼散射增强效应则主要由两层银纳米粒子之间耦合作用所致 .两种不同的耦合作用所产生的增强效应大致相近 .

Ordered mono- and double-layer structures of silver nanoparticles on smooth silver substrates were fabricated by self-assembly technique, where 1,4-benzenedithiol and p-aminothiophenol were used as the coupling molecules, respectively. The results of surface-enhanced Raman spectroscopic characterization shows that Raman scattering of the coupling molecules in the self-assemblies is greatly enhanced. The results demonstrate that the enhancement of 1,4-benzenedithiol results from the electromagnetic coupling of the smooth silver substrate with the mono-layer of silver nanoparticles, whereas the enhancement for p-aminothiophenol arises from the coupling interaction of two layers of silver nanoparticles. The enhancement effects in both cases are comparable to each other.